High efficiency plant for making steel

Abstract

A method of making steel comprising assembling a steelmaking furnace, a thin strip caster, and a mold caster, inputting to a computer data on demand and customer requirements for production output, raw materials, furnace availability and capacity, ladle treatment for casting, sequence schedules and through-put, capacities and variability, forecasting by processing by computer from the inputted data a production schedule for the steelmaking furnace and ladle treatment, and sequence schedules for the thin strip and the mold casters as a function of molten metal availability, the thin strip and mold caster sequence schedules and through-put, and demand for production output, directing production of molten metal alternatively to the delivery systems of the thin strip caster and mold caster responsive to said forecasting, and varying during casting the rate of metal delivery through the delivery system of the thin strip caster responsive to molten metal availability and the mold caster through-put.

1. A method of making steel comprising:
 (a) assembling a steelmaking furnace capable of melting and making molten metal for delivery to a first metal delivery system and a second metal delivery system, 
 (b) assembling a thin strip caster capable of continuous casting of steel strip having a thin strip production output, the thin strip caster comprising a pair of casting rolls having a nip therebetween for delivery of thin strip downwardly there from, the first metal delivery system capable of providing molten metal forming a casting pool between the casting rolls above the nip with side dams adjacent the ends of the nip to confine the casting pool, 
 (c) assembling a mold caster capable of continuous casting of steel semi-finished products having a semi-finished production output, the mold caster comprising a casting mold capable of producing one or more strands, the second metal delivery system capable of introducing molten metal into the casting mold, 
 (d) inputting to a computer data on
 demand and customer requirements for thin strip production output and semi-finished production output, 
 raw materials for the steelmaking furnace, 
 steelmaking furnace availability and capacity for making molten steel, 
 ladle treatment for casting, and 
 thin strip caster and mold caster sequence schedules and through-put, capacities and variability, 
 
 (e) forecasting by processing by computer from the inputted data
 a production schedule for the steelmaking furnace and ladle treatment, 
 a sequence schedule for the thin strip caster, and 
 a sequence schedule for the mold caster 
 
  as a function of
 molten metal availability for casting in the strip caster and mold caster, 
 the thin strip caster and mold caster sequence schedules and through-put, and 
 the demand for thin strip production output and semi-finished production output, 
 
 (f) directing production of the molten metal from the steelmaking furnace and ladle treatment alternatively to the first delivery system of the thin strip caster and to the second delivery system of the mold caster responsive to said forecasting, and 
 (g) varying during casting the rate of metal delivery through the first delivery system responsive to molten metal availability and the mold caster through-put. 
 
     
     
       2. The method of making steel of  claim 1 , where the steps of inputting the data to the computer and forecasting by processing by the computer is done intermittently during steelmaking. 
     
     
       3. The method of making steel of  claim 1 , where the steps of inputting the data to the computer and forecasting by processing by the computer is done continually during steelmaking. 
     
     
       4. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace takes into account variable speed of thin strip casting and variability in thickness of cast strip by the thin strip caster. 
     
     
       5. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace takes into account changing the rate of metal delivery through the first delivery system and the second delivery system during casting. 
     
     
       6. The method of making steel of  claim 1 , where at least one of the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace comprises:
 determining a desired rate of metal delivery through the first delivery system to the thin strip caster as a function of the molten metal availability for casting and a desired mold caster through-put rate; and 
 selecting a caster speed and strip thickness of the thin strip caster corresponding to the determined rate of metal delivery through the first delivery system. 
 
     
     
       7. The method of making steel of  claim 6 , where the desired rate of metal delivery through the first delivery system is a function of demand and customer requirements for thin strip production output. 
     
     
       8. The method of making steel of  claim 6 , where the desired mold caster through-put rate is a function of demand and customer requirements for semi-finished production output. 
     
     
       9. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace include:
 varying casting by the thin strip caster as a function of the amount of molten metal for the second delivery system for continuous casting by the mold caster. 
 
     
     
       10. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace include:
 varying the mold caster through-put as a function of the amount of molten metal desired for delivery by the first delivery system to the thin strip caster. 
 
     
     
       11. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace include:
 varying the thin strip caster through-put as a function of the amount of molten metal desired for delivery by the second delivery system to the mold caster. 
 
     
     
       12. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace take into account the preparation of the molten steel for casting by ladle metallurgical furnace, degassing the metal, or a combination thereof. 
     
     
       13. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace include taking into account profitability in making the semi-finished production output and the thin strip production output. 
     
     
       14. The method of making steel of  claim 13 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace takes into account profitability as a function of customer requirements. 
     
     
       15. The method of making steel of  claim 1 , where the steps of forecasting by processing by the computer and directing production of the molten metal from the steelmaking furnace takes into account market parameters for the semi-finished production output and the thin strip production output by the mold and thin strip casters. 
     
     
       16. The method of making steel of  claim 15 , where the market parameters include at least one selected from a group consisting of steel prices, market indices, market steel capacity, and market steel demand for the semi-finished production output and the thin strip production output.